LIGHTHOUSE

by

Michael SharaAmerican Museum of Natural History Astrophysics Department79th Street at Central Park West

New York, NY 10024

and

Jack McDevitt Cryptic, Inc. 57 Sunset BlvdBrunswick, GA 31525

Length: 6000 Wds

Lighthouse

The applause after a dissertation defense is always polite,

sometimes cool, but rarely sustained. Kristi Lang smiled and

blushed as all fifty members of her department rose to their

feet and cheered. Her fellow graduate students were the rowdiest

of all, whistling and banging their coffee cups in unison on

chairs and table tops. Greg Cooper, the department head and her

mentor, let it go on for a full minute.

"Ladies and gentlemen," he said finally, "thank you very

much."

If anything, the noise intensified.

He needed a gavel.

Kristi stood, engulfed in the moment. She nodded, raised

her hand, mouthed a thank you. A fresh round of applause, and

finally it began to lessen.

She had discovered a new type of astronomical body. A

special kind of brown dwarf. They were calling it a chimera now,

but Greg had told her yesterday that they'd eventually be

referred to as Lang Objects.

Greg was tall and thin, with an angular jaw, angular nose,

dark hair, intense eyes. His students referred to him as

Sherlock Holmes because of his world-class problem-solving

skills and his intensely mediocre abilities with a violin. "All

right," he said, signaling for quiet. "Let's pull ourselves

together."

That brought laughter.

"I wouldn't want to cancel the wine and cheese."

The people around her were reaching for Kristi's hand,

patting her on the back. Tim Rodgers, tanned and good-looking

and brilliant, gave her an approving smile. He was impressed.

Maybe even envious.

The time honored Q and A had to be observed. Greg called

for questions. Hands went up. He stepped aside and gave her the

lectern.

Tim remained standing while the others took their seats. He

was finishing his own thesis, and had been, until recently, at

the top of everybody's list of People Who Would Go Somewhere.

Now he was a distant second.

"Okay, Kristi," he said, "you've established the existence

of a new class of object. How'd it happen?"

The explanation was simple enough. She'd been doing

analytical studies of billions of brown dwarfs and had noticed a

few anomalies. Way too much deuterium. But that wasn't the big

news. She was holding that for later.

"We eventually found two thousand oddballs," she said.

Brown dwarfs were failed stars. The chimeras, the Lang Objects,

were anomalous. Odd. And not easy to account for with

conventional physics.

"You briefly mentioned actinides," came another question.

"But I don't see the connection. Please elaborate."

Kristi smiled and tried to look modest. "Think DNA," she

said. "Common origin. Common purpose."

The comment puzzled everyone. Brows furrowed. They

whispered to one another and waited for her to explain herself.

#

In fact, her inspiration had come that past summer from a

set of police blinkers mounted over a cabin on Kilimanjaro.

Hemingway's mountain. Now the site for the Yuri Artsutanov

Space Elevator. Kristi had been on her way to the Clarke

Research Station, poised overhead in geosynchronous orbit. She

was hunting for the photons that she hoped would help explain

the existence of the anomalous chimeras.

There were nearly two thousand of them, all young,

concentrated in the spiral arms of the Milky Way, interlopers,

deuterium-rich freaks that had no business existing. Clad in

shorts and a Columbia University t-shirt, Kristi drove a Jeep

across the savanna. The sky was heavy with clouds, and the smell

of cool moisture hung in the late morning air. Storm coming, and

she was already late. If she didn't hustle, she stood a good

chance of missing her ride. The weather guy had said clear,

bright and sunny, beautiful weather. She'd spent the last few

months completely absorbed by her research, had analyzed a

million images, looked for the needle in a billion haystacks,

written a killer proposal that even Greg Cooper in his Holmes

role couldn't fault. But here she was going to be left standing

at the station. Scheduling rides on the Yuri was no easy

proposition.

Not that it would matter in the end. Jeff would make the

observations and deliver the petabytes to her account. They'd be

perfectly de-biased and flat-fielded, even if she never floated

through the observatory hatch. Still, the karma would be wrong.

It was once in a lifetime, and she needed to be there when the

evidence came in.

#

The rim of Kibo, the summit crater, popped momentarily into

view as she passed three thousand meters, and then promptly

vanished into the gathering clouds. Raindrops began to spatter

against the windshield. She started the wipers. The road was

wide and designed to take heavy traffic, but it was still uphill

all the way, sometimes at an almost impossible angle. The rain

intensified, and pounded on the roof.

She slowed down as visibility dropped to about fifty

meters. A truck passed going the other way, and a burst of wind

pounded the Jeep and water blasted across the windshield.

Her cell phone chimed. "Kristi." It was Kwame Shola, the

chief of operations at Yuri.

"How you doing, Kwame?"

"Not so good. Where are you now?"

"On the way."

"Okay. But take it easy. We got snow like mad up here.

Weathermen missed it completely."

Great. Just what she needed. "All right," she said.

"No heroics, please. If you need it, we have a climber

cabin at five thousand meters. Combo is 2718."

"Twenty-seven eighteen."

"Remember 'e'."

'e,' of course, lower case always, was the base of the

natural logarithms, equaling 2.718281808... on into an infinity

of digits. "Okay," she said. "I've got it."

Greg had been ambivalent about her working with the

chimeras. Don't know where you're going to go with them, he

said. You could wind up producing a lot of data and still have

to throw up your hands and admit you don't have a clue what they

are or why they even exist. Put the idea on hold, he told her.

Confine the research to more conservative areas, at least until

you've wrapped up your doctorate and gotten an appointment

somewhere. He was right, of course. The path of guaranteed

success. But she was fascinated by the objects. Her father had

always told her to follow her instincts. And her instincts took

her right into the shadow of the deuterium dwarfs. They were so

intriguing, so difficult to explain, that she simply could not

resist.

She had never wanted to be anything but an astronomer. Her

father, who'd been a high school science teacher, had brought

home a pair of image-stabilized binoculars from the third Gulf

War. When he gave them to the little redheaded six-year-old, she

was transfixed. The moon had craters and tall mountains. Jupiter

was a tiny disk with moons of its own. And the Milky Way was a

glittering pathway of stars. Distant suns, her father had

explained. Countless millions of them. Some just like ours, some

a lot smaller.

Why, Daddy, why are some of the stars different from the

Sun?

He'd smiled and told her he didn't know, but that she could

figure it out if she wanted when she grew up.

And one evening, in the Big Dipper, she'd discovered Mizar.

Her father had been on the porch with her and she'd screeched at

him, "Daddy, they're touching!" Twin stars. Over the next twenty

years, her father could always get a laugh from her by repeating

the phrase in a rising falsetto. But in fact, as she learned

later, there were five stars in the Mizar system. By her first

year in graduate school she'd found a brown dwarf companion to

the five. And used it as a clock to age-date the system. Her

Astrophysical Journal letter hung framed in his den. But he got

nervous whenever he knew she was going up to the Clarke Station.

#

The rain turned to sleet and Kristi slowed the Jeep to a

crawl. Her defroster was rapidly losing its battle with the

Tanzanian snowstorm. She could no longer see the summit. A burst

of wind shook the Jeep.

She tried to call Kwame for a weather update, but he wasn't

answering. Something big with lights roared past her, going down

the mountain. She jerked the wheel hard, hit the brakes, spun

across the icy muck, and slid off onto the shoulder.

Maniac.

She sat listening to the sound of the retreating truck.

Then she pulled carefully back onto the highway. It was getting

dark.

She picked her way uphill, past boulders and patches of

lichen. Occasionally the road emerged along the edge of a

precipice and she could look out through holes in the clouds

across the savanna. Then the clear patch was gone and the road

was winding up through the night while rain and sleet whipped

across the windshield. She began to wonder whether she'd missed

the 5000-meter signpost when her headlights swept over it. She

didn't see a cabin anywhere, but it didn't matter because she

had no interest in missing her ride. There was still a chance,

if the weather broke, that she could make it.

The cell phone chimed. Kwame. "How you doing, Kristi?"

"I'm doing just dandy."

"You find the cabin yet?"

"Negative. Doesn't matter. I want to get up there before my

ride leaves."

"Kristi, they've canceled it. I told you that."

"No, you didn't."

"Why did you think I wanted you to find the cabin? They're

going to try again in the late morning."

"Okay."

"Go to the cabin."

"I'm past it."

He sighed. "Can you get back to it?"

She looked behind her, down the road. It was dark and cold

and she could barely see the edge of the highway. "I guess."

"Do that, then. Don't try to come up tonight. It's too icy.

Already had one truck go off the road. Driver was damn near

killed."

"Okay."

"You sure you can find the cabin?"

"Sure. Relax. Everything's fine, Kwame."

It was about a kilometer back, maybe two. She put the phone

down on the seat and peered out onto the highway. Nothing coming

in either direction.

She cut the wheel and started to turn. She couldn't judge

how wide the road was, so she was careful not to go too far

forward. She reversed and started back. Felt the rear wheels

lose traction. Tried to go forward again. But the Jeep continued

sliding back. And down.

My God, she was going into a ditch.

She fought the wheel, damning the Jeep and the highway and

the storm. But it did no good and the vehicle slid sideways off

the shoulder and crunched over a large rock into a snowbank. She

shifted gears and gunned the engine. The wheels spun, the Jeep

struggled forward a few centimeters, dug a deeper hole, and slid

back in.

Damn.

She called Kwame.

"You want me to come get you?"

She looked down at the tee-shirt and shorts. The heater was

on full blast. "No," she said. "Don't do that. I'll make for the

cabin."

"Okay. Be careful."

"I will."

"Call me if you have a problem."

It was frigid out there. Better was to sit tight and wait

for somebody to come along.

#

There are twenty-one billion brown dwarfs in the Milky Way,

give or take. Kristi had found and mapped almost every one of

them. "The light output of brown dwarfs alternates wildly

between adjacent wavelengths, Dad," she'd once explained to him.

"My infrared survey filters are tuned to just the right

wavelengths, so all other stars appear dimmer. The hard part is

keeping track of them all, and repeating the survey a year later

to measure their motions. Then we have to sift out all the weird

quasars that sneak through the filtering. MEGASPEC catches them

all." Brown dwarfs were not massive enough to ignite

thermonuclear fires in their cores. They would always be failed

stars, their dim glow generated by cooling and contracting.

"Ninety-nine point six nines" was the delicious phrase she used

in colloquia to describe her survey's thoroughness. No one had

ever done that for brown dwarfs. Hell, nobody had ever done that

for anything in astronomy. She had nailed the definitive sample

for all time. Sure, there'd be a few hundred hiding behind

luminous primaries, or lurking directly in front of distant

quasars, but she'd gotten the rest. There was no arguing with

twenty-one billion spectra and parallaxes and radial velocities

and proper motions. She could tell you what the temperature of

each one had been a million years ago. And where each one would

be ten million years from now. Her census was the last word on

how the Galaxy's failed stars had arranged themselves during the

past thirteen billion years. She could chart the few ancient,

metal-free brown dwarfs along their orbits looping far out into

the Milky Way's halo. The larger population of metal-rich

youngsters, the astronomical infants, clung to the plane of the

Milky Way.

The chimeras (she settled for the term "anomalous objects"

in her seminars) had been culled from her complete sample of

twenty-one billion by statistical sifting and weighing. Every

one of them had a spectrum that called attention to itself, that

defied everything she thought she knew about this type of

object. The surface abundance of deuterium was impossibly high.

It was a heavy isotope of hydrogen, with one proton and one

neutron, and the Big Bang had made only a pinch of it, before

stingily shutting off production just three minutes after

creation. There was no known way that any planet or star or

galaxy or anything else was going to concentrate the primordial

trace of deuterium to more than a pinch. The textbooks

maintained that anything over 0.001% was impossible. Yet Kristi

had found two thousand brown dwarfs whose composition was nearly

fifty percent deuterium.

#

It was frigid out there. The engine, which had been keeping

her reasonably warm, coughed and died.

She tried to restart it.

Tried again.

When she opened the door, she smelled gasoline and stuck

her head outside. There was a stain on the snow. She must have

punctured the tank. Or the gas line.

The mountain highway remained silent.

Okay. Crunch time. Can't stay here. It was already getting

cold.

She checked to be sure she had her pen flashlight. Staple

for astronomers. She turned it on and pointed it out the window,

where the beam got lost in the snow. There was a travel bag in

back with light clothing, and she could try putting everything

on, but she was still going to get pretty cold out there.

It was only a kilometer back, two at most. She could manage

that. She pulled her bag from the back seat and began sifting

through her clothes.

She put on two extra blouses. They weren't going to help

very much, but she'd take what she could get. And there was a

sweater. She pulled it around her shoulders. Felt like an idiot.

She thought about Tim. He was the romance that had never

happened. Partly her own fault. Always too busy. And her father,

safe and warm in their North Jersey home.

Love you, Daddy.

#

The wind tried to take the door out of her hand. She hung

on, dragged her bag out of the backseat, and chunked the door

shut. The snow was driving at her, and it seemed to be coming

from all directions.

The ditch was shallower than it had seemed, but the sides

were ice, and she had to climb out on hands and knees. When she

finally stood on the road, she fished out her penlight and

turned it on. The world around her looked desolate.

The wind cut through her garments and chilled her to the

bone. It literally took her breath away. She was wearing canvas

shoes and her feet got cold before she'd gone a dozen steps.

The penlight beam outlined ditches and a snow cover fading

away into the night.

She pressed her arms against her chest and tried to push

the cold out of her mind. Move out, Scout, she told herself.

There's shelter back there somewhere.

Her toes went numb. A blast of wind knocked her down. When

she got up, she no longer had the penlight. Didn't know where it

had gone. She'd been carrying it in her right hand, but the hand

had no feeling.

For the first time in her life, she felt real fear.

This was the darkest place she'd ever seen. There was no

glimmer of light anywhere. The edge of the road was no longer

visible. The world had vanished, had become a place utterly

without borders, without any distinguishing features, other than

the snowflakes that continued to rush at her.

She thought about calling Kwame. But she couldn't do that.

What would he think? Poor woman can't get from the Jeep to the

cabin without getting in trouble.

It was hard to breathe. Her lungs hurt, and tears froze on

her cheeks.

She pushed her hands into her sweater pockets and started

out again. Hell with it. Didn't need the light anyway.

Still no sign of anything. Not of a cabin. Not of the

marker.

The terrifying truth was she could walk right past the

marker and never see it.

She was counting her steps now. Roughly thirteen hundred to

a kilometer. Right? She'd already come about five hundred. Or

maybe one hundred. Somewhere, below her, she heard the sound of

a plane.

She tried to pick up her pace. Keep moving. Keep watching.

And think about something else. Think about Daddy's rising

falsetto. If she was lucky the marker and the cabin would be

right next to each other. Why, Daddy, they'd be touching!

#

After a while, she became convinced she must have missed

it. She debated starting back toward the Jeep, and looked

helplessly in both directions. Couldn't have been this far.

She'd only passed it about three minutes before she'd stopped

and gone into the ditch. She'd been traveling about fifteen,

twenty at most. How far was that?

She couldn't figure it out. She'd begun to feel as if she'd

withdrawn into a cave, was looking out through her eyes from a

safe place somewhere back of her nose.

That was funny, Lang. Laugh.

Ha.

Still walking forward, she flipped open the cell phone.

Time to confess. Tell Kwame she was in trouble.

Off to her left, a soft orange glow appeared in the blowing

snow.

#

Nothing about this class of brown dwarfs made sense. Their

composition was just under fifty percent deuterium. Crazy

enough. The remaining half was mostly hydrogen, the ordinary

one-nucleon variety. No problem with that, except that it left

little room for helium, which, in most of the chimeras, totaled

less than one percent. It was their larger than normal size that

tightly constrained the helium abundance. Even Tim, the

brightest young theorist she knew, had to concede the point.

Every other cosmic object is born with the allotment imprinted

by the Big Bang: a full twenty-seven percent. So where was the

rest of the helium?

There was no way to hide helium in a still-warm brown

dwarf, and all of the chimeras were warm Galactic infants.

Kristi's deuterium reservoirs mocked her, because they simply

could not exist.

#

The orange glow hung momentarily in the darkness. Then it

went off.

Somewhere, far away, she heard a snarl. Leopards don't

climb this high, do they?

She started walking toward the spot where she'd seen the

light. It came on again. And went off.

It had to be the cabin.

She moved closer. Saw the 5000-meter marker to her right. A

metal sign, white with black numbers.

The light blinked on again. More distinct this time. It was

a police car beacon. Set on a rooftop.

Thank God.

Wooden steps led up onto a porch. She saw three dark

windows and a door. There were wicker chairs on the porch, and a

table. She climbed the steps, felt the wind cut off as she came

into the shelter of the cabin, and tried the doorknob.

It was locked.

A number pad was bolted to the frame. The combination. What

was the combination?

Kwame had said, Remember 'e'. Twenty-seven eighteen.

The beacon kept flashing. Every few seconds. It reflected

off the snow cover, giving her just enough light to work with.

She got it wrong the first time, and for a heart-stopping

moment she feared the lock was frozen. Or she'd been mistaken.

But the second try was golden and the door clicked. She pulled

it open, kicked the snow out of the way, and half-fell through

onto a stone floor.

The interior was frigid.

She shut the door and looked around. There were more wicker

chairs and another table. A long row of solar batteries powered

the beacon. A cot was set against one wall. And a pot-bellied

stove stood in the middle of the room. She looked around for a

thermostat. Saw nothing.

Someone had left a box of matches, and a yellowed copy of

USA Today.

Kristi stared at the stove. My kingdom for a few logs. She

could go outside and root through the storm. Maybe get lucky.

But the furniture was more convenient. She picked up one of the

chairs and brought it down hard against the floor.

It held together.

She tried again.

It was remarkably resilient. She stumbled around the cabin,

looking for an axe, gave up, and went back to beating the chair.

Desperation lent strength and, finally, it came apart. Enough,

at least, that she could jam it into the stove.

Ten minutes later she sat in front of a fire that, if it

was not quite blazing, nevertheless served to take the freeze

off the room. She called Kwame. "I'm in."

"Good," he said. "I was getting worried. Don't leave the

cabin until the storm stops."

"Have no fear. One problem--."

"Yes?"

"I left my transportation in a ditch."

"You were not hurt, I hope?"

"No, I'm fine."

"Okay. I'll send a truck down as soon as the road's clear."

"Kwame?"

"Yes?"

"Send sandwiches, too."

#

Her toes began to recover some feeling. She found a blanket

in a closet. It smelled of cigarettes but she didn't care. She

warmed it on the stove, wrapped herself in it and closed her

eyes.

She was wide awake. She'd have liked to read. But even if

the light had been adequate, she'd left her briefcase in the

car. In it were copies of Physics Today and People, which she'd

brought for the skyride. And a marked-up version of her

dissertation. Once at Clarke, there'd be no leisure. She

expected to spend six days doing nothing but observing, reducing

data, and sleeping.

The wind shook the cabin. And suddenly her eyes felt heavy.

Her head drifted back, and the sounds of the fire, the sense of

warmth, faded.

She woke a couple of times, and jammed more furniture into

the stove. And once, toward the end, she saw gray light in the

windows.

#

The nuclei were piled high in her office. Thousands of

deuterons. In the drawers. On the keyboard. Scattered across her

desk. Each deuteron's green neutron and blue proton were

morphing back and forth, into each other, a colorful display of

the strong nuclear force in action.

Get the vacuum cleaner. Where was the vacuum cleaner?

She was still looking when a hand touched her shoulder.

"Hey, Kristi. How you doing?"

Kwame.

The fire had gone out but the stove still held some heat.

"I'm okay," she said.

"Good. The road's clear. If you're ready we can head out."

Kwami was a middle-aged African, not quite as tall as she. His

hair had gone white, and his features suggested he'd known some

difficult times. He was wrapped in a heavy parka with the hood

down. His dark eyes were shining, and he spoke with a British

accent.

She pulled the blanket more tightly around her while she

pushed her feet back into her shoes. "I'm ready," she said.

"You don't want to take a shower first?" He nodded toward

the washroom, but kept a straight face.

A snow plow waited outside. The sun was behind some white

clouds. It was relatively warm, and the cabin roof was lined

with melting icicles.

She climbed into the passenger's seat and looked back at

the police light. "If it hadn't for the blinker," she said, "I'd

never have found the place."

He nodded. "That's why it's there, Kristi."

She thought about suggesting he add an ax to the amenities.

And maybe some canned goods. But, on second thought, maybe

another time.

He passed her a jelly donut.

#

Kristi had been to the summit of Kilimanjaro four times

before, but the sight of the base towers and the nanowire ribbon

stretching up to infinity was as exhilarating as ever. "It

hasn't left yet?" she asked him.

"No. They've been waiting for you."

It wasn't critical that she be on site while her data were

collected. But Greg had designed MEGASPEC and Kristi had written

most of its software to confirm brown dwarf candidates, so a

trip to recalibrate the million-object spectrograph was

justified. And there would never be a time she'd pass on an

opportunity to go up to the station, to see the home world from

36,000 kilometers. There was still a little kid in her

somewhere. She'd commented along those lines once to Greg and he

said it was true of everyone in the sciences who was worth a

damn.

Kwame apologized that there was no time to shower and

change. Have to do it in zero-gee.

"I'll try to keep away from the other passengers," she said.

"Ah. It is their loss."

They pulled up at the front door of the terminal, and she

thanked him for maybe the fifth time. Then she was hurrying

through the reception area and someone came alongside to help

with her bag and briefcase. Moments later she cleared the entry

ramp, and hatches shut.

There were roughly a dozen other passengers. About half of

them were tourists, including two kids. They looked curiously at

her as the carbon nanowires stiffened and the elevator lifted

away from Kilimanjaro. Minutes later she caught sight of Lake

Victoria. They rose through the clouds, and the Atlantic came

into view. And eventually she was looking down at the entire

continent, from the Cape of Good Hope to the Nile delta.

#

Two hours out, at an altitude of 8000 kilometers, she got a

sandwich and coffee from the convenience counter and settled

down at one of the viewport tables to enjoy the ride. Closer to

the chimeras, she thought. Well, not really, but the illusion

was there as she soared ever higher.

She wished there were starships. She'd love to have an

opportunity to go out and look at one of the things, close up.

She knew how it would appear, of course. She had virtual brown

dwarfs on call back home. They were Jupiter-sized spheres, red-

brown, with mottled clouds floating in the atmosphere. The

clouds were iron hydride, and of course the dwarf would be

glowing, rather like a coal recently plucked from the fire.

She visualized it, and somehow she found herself thinking

about Kwame's police lights.

Someone came over and asked if he could share the table. Of

course. He was a young man, and she realized immediately he was

on the make.

"...Going to be pretty well tied up while I'm here," she

was saying.

He was a technician of some sort. Dull-looking. Thought

well of himself. "Of course," he said. "But all work--."

She heard him out, and smiled when appropriate. "They pay

to send me up here," she said, as if she were making a major

sacrifice. "...Don't want me sitting around."

The police lights. She stared through the young man into

the deep night of the 5000-meter elevation, saw the soft orange

glow, blinking on and off.

And suddenly she understood.

#

"I don't buy it, Kristi," Greg said. She had him on the vid

relay, from his office. "There's got to be a natural mechanism

at work. Maybe high pressure chemistry. Maybe magnetic fields.

Maybe radiative levitation. Geochemical processes can

concentrate minerals by orders of magnitude on Earth, so why not

deuterium on the surfaces of brown dwarfs under far more exotic

conditions?" He sounded really concerned. It was why she liked

him so much. He was worried about what would happen to her

career if she tried to go public with her notion. She imagined

it was hard for him not to say, You're skating at the edge of

academic disaster. Blow your reputation now and you'll always be

at the fringe.

"I admit," he said, "that fifty percent deuterium is far

out. But whatever did this could also bury the helium. We just

don't know enough."

"I think it's true," she said.

"It could be. Anything's possible, Kristi. But think about

what the professional price will be if you go off half-cocked,

and then someone finds the real explanation." Then, more gently:

"I'll go this far: Get two more pieces of independent evidence.

If your idea stands up, Galileo will have to move over."

#

While the Earth dropped away, she worked on her computer.

An hour later, still on the elevator, she raised a fist in

triumph. The act drew the attention of several of her fellow

passengers. She didn't care. She had a match. In fact, the

chimeras, almost the entire sample of two thousand, except two,

showed up at the same sites listed in the all-sky X-ray source

catalogs as black holes. That gave her a stunning 99.9%

correlation. How much proof do you want, Greg?

For the next five hours she looked fruitlessly for other

patterns. She was still engrossed in her analysis, and trying

hard to keep her sense of exhilaration under control, as the

elevator began its approach to the station.

An attendant asked her to return to her seat and buckle in.

She felt indestructible at the moment, but she happily complied.

Galileo was a piker.

An orange light was blinking on the link-up collar. It

reminded her of Kwame's beacon, and she smiled. A series of

thuds reverberated through the hull as the elevator docked and

the airlocks mated. Hatches opened and the passengers floated

through into the connecting tube. The tourists would be headed

for the hotel. The others scattered in different directions.

Jeff Fields, who ran the observatory programs, was waiting

for her. "Jeff," she said, "I want you to do something for me."

"Okay," he said. "What do you need?"

"Tomorrow, before we make any observations, I need you to

change to the highest resolution grating."

#

Standing at the lectern before her mentors and her peers,

Kristi had deftly fielded a dozen questions about her analyses

and catalog. The privilege of asking the final question

traditionally went to the senior graduate student. Tim. She'd

seen him writing while she spoke, scratching out lines, making

faces, writing again. When the moment came, he stood. "Sorry,

Kristi," he began. "Nobody here is more anxious for you to be

right. But I still don't get it." He glanced down at his notes,

looked over at Greg, and plunged on. "Your high-res spectra and

gravitational redshifts unquestionably prove that every one of

your chimeras is eight Jupiter masses, and that each is orbiting

something every year or so." He took a deep breath. "The X-ray

source coincidences are a convincing argument that the

somethings are black holes. But black holes can't concentrate

deuterium or hide helium. Black holes were all once stars way

too luminous to have formed with sub-brown dwarf companions in

the first place. And, worst of all, your chimeras are too low in

mass to ignite as brown dwarfs, yet they radiate like hot brown

dwarfs."

The others round the table were looking anxiously from Tim

to her. A few whispers began. "In theory," Tim continued, "your

chimeras can't exist, right? But they do. So what's going on?"

You know, she thought, he really is good-looking. But not

as quick on the draw as I'd thought.

He started to sit down, but got up again. "Kristi, you must

have some idea how to explain these things?"

She looked over at Greg. He was gazing out the window at

the beautiful autumn day. Then his eyes met hers. And he nodded.

Do it.

Her paper had been accepted yesterday by Nature. Letting

the cat out of the bag now wouldn't jeopardize anything. She'd

kept everyone, other than Greg, in the dark. Even Tim.

"We classify anything less than thirteen Jupiter masses as

a planet," she began, "because these objects never develop

sufficient internal pressure to ignite their deuterium, let

alone their hydrogen. Yet we now see objects eight times

Jupiter's mass displaying surface abundances that can only come

from deuterium burning. That's impossible with one thousandth of

a percent deuterium. But deuterium ignition works just fine if

these objects are born with eight Jupiter masses and fifty

percent hydrogen and fifty percent deuterium, and they’re

sparked". She was looking directly at Tim, who was sitting

looking lost.

"By analogy," she continued, "a trace of air mixed with

gasoline is stable, but a fifty-fifty mixture is highly

combustible. A spark sets off a conflagration. Since nature

can't make or ignite fifty-fifty deuterium-hydrogen objects,

especially near the kind of massive stars that collapse into

black holes..." she paused for effect, "...it's hard to see that

the chimeras can be anything other than artificial."

The room went dead silent. A gust of wind struck the

windows and she thought briefly of Kwame's cabin. At the

doorway, a small group of professors had gathered. She wondered

whether Greg had alerted his colleagues.

History being made today in the Bishop Library.

Tim looked stunned. "Kristi," he said, in a voice she did

not recognize, "you're not making this claim seriously?"

"I am," she said. A wave of guilt passed through her. Maybe

she should have taken him aside. Warned him what was coming.

"They're artificial as in synthetic. As in not made by nature.

As in manufactured by Little Green Guys. I would argue they were

deliberately placed in orbit around black holes which have no

other companions.

"At first I suspected they were an experiment, test objects

of some kind. But that would be an experiment hugely wasteful of

resources when you could get away with masses a million times

smaller."

The professors at the door were crowding into the room.

"No, the chimeras' creators needed something self-luminous,

something that would last a long time, but something that would

cost as little as possible because they had to make two thousand

copies. A fifty-fifty deuterium-hydrogen mixture is the nuclear

fuel that can be ignited in the lowest possible host mass. It's

the cheapest interstellar beacon you can make if you insist on a

hundred-million year warranty. Nature can't make these objects.

But somebody can." She took a sip of water as her words sank in.

"The helium makes sense,too," she continued. "It's the ash,

the by-product of pure deuterium-hydrogen fusion, brought up by

convection from the core. The helium content of the chimeras is

limited to one percent or less because they're all younger than

a million years. Each one will continue burning its core

deuterium and will shine at its present luminosity for another

hundred million years."

Tim was going to say something else but Greg broke in. He

was beaming. "Kristi, two of the chimeras are not associated

with black holes. What can you tell us of them?"

"One of them," she said, "is moving at nearly three percent

of the speed of light through Taurus. A second is in orbit

around a G-dwarf in Scorpius. It's just under seven Jupiter

masses, the lightweight of the entire sample, and the least

luminous. I really don't know for certain, but I'd speculate

that the first object is being towed or pushed toward a newborn

black hole. And I wouldn't be surprised if the second one is on

the assembly line."

The applause was tentative this time. Until the people at

the doorway joined in.

#

Greg had a final word: "My initial reaction, when Kristi

ran all this by me, was the same as Tim's. But there's one more

piece of evidence that convinced me. Kristi?"

She was at her charming best, at a moment she would always

remember. "A thirty-meter telescope at geosync orbit," she said,

"is an amazing instrument. But the chimeras are faint and I

couldn't find anything but deuterium, hydrogen, and helium in

any of their spectra. When I realized that they had to be copies

of each other, I removed the Doppler shift of each one and then

co-added the two thousand spectra. The result is almost fifty

times more sensitive to trace elements."

She touched the video controller and the summed spectrum

appeared, undulating and smooth, with four sharp, narrow dips.

"See those four absorption lines? Only one element makes those

lines. Plutonium. The nastiest, most dangerous substance we

know. "Each chimera is seeded with pure Plutonium-244, which

will last as long as the chimera itself. It's the closest thing

to a universal skull and crossbones I can imagine.

"Ladies and gentlemen, the chimeras are beacons. Celestial

lighthouses. Space-faring travelers are being warned away from

the shoals. Away from the Milky Way's two thousand solo black

holes, which are otherwise nearly undetectable."

"Magnificent," said one of the professors. "If true."

She smiled, as her audience collectively let out its

breath. "The evidence is all there, Professor. And, if Greg

doesn't mind, I could use a glass of Cabernet. If we could quit

now?"